A number of ablation treatments have been used to treat tumors or other tissue in a patient's body. In some cases, ablation therapy may be used to treat tumors that are not responsive to chemotherapy or other techniques. For example, primary liver cancer or hepatocellular carcinoma (HCC) is an aggressive neoplasm that may not respond well to intravenous chemotherapy.
The choice of treatment for HCC normally depends on severity of underlying liver disease, size and number of lesions, location of lesions, ability to detect them with MRI, non-contrast or contrast CT, or ultrasound, and local expertise. Conventionally, physicians have employed RF ablation or microwave ablation to destroy the tumor tissue with heat, combined heating with coadministration of liposomes containing a drug, cryoablation to freeze a tumor, hepatic arterial drug infusion, bland arterial embolization, chemotherapy combined with arterial embolization, selective internal radioembolization using radioactive labeled iodized oil or radioactive microspheres as the embolic agent, external beam radiation therapy, or direct injection of a single agent (e.g., ethanol, acetic acid, hydrochloric acid, hot saline, or sodium hydroxide) to ablate the tumor.
One low cost and less invasive method is percutaneous injection of one of either ethanol or acetic acid. Although high-cost RF or microwave ablation systems are generally not employed with this method, conventional single-agent injections have raised concerns. The injection of a single agent such as acetic acid may increase the acid load in the patient, which cause toxicity problems and possibly renal failure. The injection of a single agent such as ethanol can also cause toxicity problems. To regulate the acid load or other toxicity problems from the injections of the single chemical agent, the dosage for each session is usually limited. Smaller dosages of the agent may generally limit the physician's ability to treat anything other than smaller tumors.